Writing for Psychology Today, dog behaviour expert and psychology professor Stanley Coren said there are some telltale signs hugs are actually stressing out your canine pals.

They include:

* Turning their heads away to break eye contact.

* Low, flat ears.

* Small "stress yawns."

* The whites of their eyes showing.

* Lip licking.

Coren wrote that when dogs are in trouble, their instincts tell them to run. A tight, fluffy hug impedes that escape route, which is what could potentially upset your pup.

To prove his observations, Coren evaluated 250 images of dogs being hugged sourced through searches on Google and Flickr. What he found was plenty of evidence.

Purestock / Getty Images / Via Creative Commons

In all, Coren said 81.6% of the photos showed dogs displaying "at least one sign of discomfort, stress or anxiety" and only 7.6% showed dogs that were "comfortable with being hugged"

For the remaining 10.8%, there was no strong sign either way.

His conclusion:

The clear recommendation to come out of this research is to save your hugs for your two-footed family members and lovers. It is clearly better from the dog's point of view if you express your fondness for your pet with a pat, a kind word, and maybe a treat.

Basically, this is all pretty devastating for anyone who knows the best thing about having dogs around is getting to hug them.

BUT DO NOT LOSE ALL HOPE. Maybe some dogs don't like some hugs from some people in some photos. But maybe your dog isn't one of those dogs.

As the New York Timespointed out, Coren may be an expert in his field but this was a blog post, not a peer-reviewed study. The dogs in the photos could have been stressed for any number of reasons, the hug only being one of them.